Drain Apparatus for Hemodialysis Machines

ABSTRACT

This disclosure relates to dialysis systems and methods. In some implementations, a dialysis system includes a dialysis machine with a fluid line and a drain line, a blood line set configured to be connected to the dialysis machine, and a drain apparatus coupled to the dialysis machine. The drain apparatus includes a chamber configured to receive an end of a patient line of the blood line set, an inlet line, an outlet line, and a valve. The inlet line has a first end configured to be coupled to the chamber and a second end configured to be coupled to the fluid line of the dialysis machine. The outlet line has a first end configured to be coupled to the chamber and a second end configured to be coupled to the drain line of the dialysis machine. The valve is configured to control flow of fluid through the outlet line.

TECHNICAL FIELD

This disclosure relates to dialysis systems and methods.

BACKGROUND

Dialysis is a treatment used to support a patient with insufficientrenal function. The two principal dialysis methods are hemodialysis andperitoneal dialysis.

During hemodialysis (“HD”), the patient's blood is passed through adialyzer of a dialysis machine while also passing a dialysis solution ordialysate through the dialyzer. A semi-permeable membrane in thedialyzer separates the blood from the dialysate within the dialyzer andallows diffusion and osmosis exchanges to take place between thedialysate and the blood stream. These exchanges across the membraneresult in the removal of waste products, including solutes like urea andcreatinine, from the blood. These exchanges also regulate the levels ofother substances, such as sodium and water, in the blood. In this way,the dialysis machine acts as an artificial kidney for cleansing theblood.

During peritoneal dialysis (“PD”), a patient's peritoneal cavity isperiodically infused with dialysis solution or dialysate. The membranouslining of the patient's peritoneum acts as a natural semi-permeablemembrane that allows diffusion and osmosis exchanges to take placebetween the solution and the blood stream. These exchanges across thepatient's peritoneum, like the continuous exchange across the dialyzerin HD, result in the removal of waste products, including solutes likeurea and creatinine, from the blood, and regulate the levels of othersubstances, such as sodium and water, in the blood.

Many PD machines are designed to automatically infuse, dwell, and draindialysate to and from the patient's peritoneal cavity. The treatmenttypically lasts for several hours, often beginning with an initial draincycle to empty the peritoneal cavity of used or spent dialysate. Thesequence then proceeds through the succession of fill, dwell, and drainphases that follow one after the other. Each phase is called a cycle.

SUMMARY

In one aspect, a dialysis system includes a dialysis machine with afluid line and a drain line, a blood line set configured to be connectedto the dialysis machine, and a drain apparatus coupled to the dialysismachine. The drain apparatus includes a chamber configured to receive anend of a patient line of the blood line set, an inlet line, an outletline, and a valve. The inlet line has a first end configured to becoupled to the chamber and a second end configured to be coupled to thefluid line of the dialysis machine. The outlet line has a first endconfigured to be coupled to the chamber and a second end configured tobe coupled to the drain line of the dialysis machine. The valve iscoupled to the outlet line and configured to control flow of fluidthrough the outlet line.

In another aspect, a drain apparatus for a dialysis machine includes achamber, a lid, an inlet line, an outlet line, and a valve. The chamberis configured to receive an end of a fluid line extending from thedialysis machine. The lid is configured to be coupled to the chamber toform a seal with the chamber. The inlet line has first end configured tobe coupled to the chamber and a second end configured to be coupled to afluid line of the dialysis machine. The outlet line has a first endconfigured to be coupled to the chamber and a second end configured tobe coupled to a drain line of the dialysis machine. The valve is coupledto the outlet line and configured to control flow of fluid through theoutlet line.

In a further aspect, a method includes emptying contents of a blood lineset of a dialysis system into a chamber of a drain apparatus of thedialysis system, closing a lid of the drain apparatus to seal thechamber of the drain apparatus, flowing a disinfectant fluid through aninlet line of the drain apparatus from a dialysis machine of thedialysis system to the drain apparatus to at least partially fill thechamber of the drain apparatus with the disinfectant fluid, and flowingthe disinfectant fluid through an outlet line of the drain apparatusfrom the drain apparatus to a drain line of the dialysis machine.

Implementations can include one or more of the following features.

In some implementations, the fluid line and the drain line are parts ofa hydraulic circuit of the dialysis machine and the dialysis systemfurther includes a dialyzer connected to the hydraulic circuit of thedialysis machine.

In certain implementations, the drain line is downstream of thedialyzer.

In some implementations, the fluid line is upstream of the dialyzer.

In certain implementations, the second end of the outlet line isconfigured to be coupled to the drain line at a location upstream of apost-dialyzer flow pump of the dialysis machine.

In some implementations, the second end of the outlet line is configuredto be coupled to the drain line at a location of the dialysis machinedownstream of a drain valve of the dialysis machine.

In certain implementations, the drain apparatus further includes a pumpcoupled to outlet line and configured to pump fluid from the chamber ofthe drain apparatus to the drain line of the dialysis machine.

In some implementations, the drain apparatus is configured to drainfluid contained in the chamber of the drain apparatus through the outletline of the drain apparatus to the drain line of the dialysis machine bygravity when the valve of the drain apparatus is in an open position.

In certain implementations, the second end of the inlet line isconfigured to be coupled to a portion of the fluid line downstream of afluid filter of the dialysis machine.

In some implementations, the drain apparatus includes a lid coupled tothe chamber and configured to form a seal with the chamber.

In certain implementations, the lid includes a vent and a hydrophobicfilter disposed within the vent.

In some implementations, the chamber includes an inner funnel coupled toand nested within an outer funnel.

In certain implementations, the inner funnel and outer funnel form anannular channel and the first end of the inlet line is fluidly connectedto the annular channel. In some implementations, the annular channel isformed between an outer surface of the inner funnel and an inner surfaceof the outer funnel.

In certain implementations, the drain apparatus further includes a pumpcoupled to the outlet line.

In some implementations, the drain apparatus further includes one ormore mechanical attachment devices coupled to the chamber and configuredto position the end of a patient line extending from the dialysismachine inside the chamber.

In certain implementations, the drain apparatus further includes a ventextending through the lid, and a hydrophobic membrane coupled to thevent.

In some implementations, the drain apparatus further includes a sensorconfigured to detect a fluid level in the chamber.

In certain implementations, the sensor includes a pressure sensorcoupled to the outlet line.

In some implementations, the sensor includes an ultrasound sensorcoupled to the chamber.

In certain implementations, sensor includes an ultrasonic sensor and anultrasonic receiver coupled to the lid.

In some implementations, the sensor includes a light transmitter and alight receiver coupled to the lid.

In certain implementations, the sensor includes one or more electrodescoupled to the chamber.

In some implementations, the lid includes one or more vent holes.

In certain implementations, emptying contents of a blood line set of adialysis system into a chamber of a drain apparatus of the dialysissystem includes connecting a patient line of the blood line set to thedrain apparatus of the dialysis machine following performance ofdialysis on a patient, flowing a saline solution through the patientline of the blood line set into the drain apparatus to flush remainingfluid in the blood line set into the drain apparatus, and disconnectingthe patient line of the blood line set from the drain apparatus.

In some implementations, the method further includes stopping flow ofthe disinfectant fluid upon receiving a signal from a sensor coupled tothe drain apparatus indicating that the chamber of the drain apparatusis filled with disinfectant solution.

In certain implementations, the disinfectant fluid dwells in the chamberof the drain apparatus for a predetermined amount of time.

In some implementations, flowing the disinfectant fluid through theoutlet line of the drain apparatus from the drain apparatus to the drainline of the dialysis machine includes opening a valve coupled to theoutlet line of the drain apparatus.

In certain implementations, flowing the disinfectant fluid through theoutlet line of the drain apparatus from the drain apparatus to the drainline of the dialysis machine includes pumping the disinfectant fluid inthe chamber of the drain apparatus to the drain line using a pumpcoupled to the outlet line of the drain apparatus.

In some implementations, flowing the disinfectant fluid through theoutlet line of the drain apparatus from the drain apparatus to the drainline of the dialysis machine includes using negative pressure generatedby a flow pump of the dialysis machine to pump the disinfectant fluid inthe chamber of the drain apparatus to the drain line.

In certain implementations, the disinfectant fluid includes a chemicaldisinfectant.

In some implementations, the disinfectant fluid is hot water.

In certain implementations, flowing the disinfectant fluid through theinlet line of the drain apparatus from the dialysis machine to the drainapparatus to at least partially fill the chamber of the drain apparatusincludes flowing the disinfectant fluid into the chamber at a ratesufficient to maintain a predetermined level of fluid in the chamber fora predetermined amount of time.

Advantages of the systems, devices, and methods described herein includeease of use for the user. By providing a drain apparatus that is coupledto the drain line of the dialysis machine, emptying and disinfecting thedrain apparatus following priming or flushing patient lines issimplified by reducing the need to drain and sterilize the drainapparatus separately from the dialysis machine. Another advantage isthat by incorporating the disinfection of the drain apparatus used forpriming and flushing patient lines with disinfection of the dialysismachine, the overall time required to disinfect the drain apparatus andthe dialysis machine is reduced. Another advantage is a reduced risk ofspills and biohazards. For example, since the drain apparatus can bedisinfected and drained while remaining connected to the dialysismachine, the need to transport the drain apparatus for disinfection, andthus risk spilling the contents of drain apparatus (e.g., patient linefluids), is greatly reduced.

Other aspects, features, and advantages will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a hemodialysis system that includes adrain apparatus coupled to a dialysis machine.

FIG. 2 is a cross-sectional view of the drain apparatus of FIG. 1.

FIG. 3 is a perspective view of the drain apparatus of FIG. 1 in an openposition with a patient line of a hemodialysis system coupled to thedrain apparatus.

FIG. 4 is a perspective view of the drain apparatus of FIG. 1 in aclosed position

FIG. 5 a schematic of a dialysate circuit of the hemodialysis system ofFIG. 1 with the drain apparatus of coupled to the dialysate circuit.

FIG. 6 is a schematic of a blood circuit of the hemodialysis system ofFIG. 1.

FIG. 7 is a schematic of the dialysate circuit of FIG. 5 with analternate coupling of the drain apparatus to the dialysate circuit.

FIG. 8 is a schematic of the dialysate circuit of FIG. 5 with analternate coupling of the drain apparatus to the dialysate circuit.

FIGS. 9-15 are cross-section views of alternate drain apparatuses forthe hemodialysis system of FIG. 1.

FIG. 16 is a schematic of a blood circuit and drain apparatus of thehemodialysis system of FIG. 1.

FIG. 17 is a cross-section view of an alternate drain apparatus for thehemodialysis system of FIG. 1.

FIG. 18 is a schematic of a blood circuit and drain apparatus of thehemodialysis system of FIG. 1.

DETAILED DESCRIPTION

Referring to FIG. 1, a hemodialysis system 100 includes a hemodialysismachine 102 to which a disposable blood component set 104 that forms ablood circuit is connected. During hemodialysis, arterial and venouspatient lines 106, 108 of the blood component set 104 are connected to apatient and blood is circulated through various blood lines andcomponents, including a dialyzer 110, of the blood component set 104. Atthe same time, dialysate is circulated through a dialysate circuit(shown in FIG. 5) formed by the dialyzer 110 and various other dialysatecomponents and fluid lines connected to the hemodialysis machine 102.Many of these dialysate components and fluid lines are located insidethe housing of the hemodialysis machine 102, and are thus not visible inFIG. 1. The dialysate passes through the dialyzer 110 along with theblood. The blood and dialysate passing through the dialyzer 110 areseparated from one another by a semi-permeable structure (e.g., asemi-permeable membrane and/or semi-permeable microtubes) of thedialyzer 110. As a result of this arrangement, toxins are removed fromthe patient's blood and collected in the dialysate. The filtered bloodexiting the dialyzer 110 is returned to the patient. The dialysate thatexits the dialyzer 110 includes toxins removed from the blood and iscommonly referred to as “spent dialysate.” The spent dialysate is routedfrom the dialyzer 110 to a drain via a drain line 112.

Still referring to FIG. 1, the dialysate circuit of the hemodialysismachine 102 is formed by multiple dialysate components and fluid linespositioned inside the housing of the hemodialysis machine 102 as well asthe dialyzer 110, a dialyzer inlet line 134, and a dialyzer outlet line136 that are positioned outside of the housing of the hemodialysismachine 102. The dialyzer inlet line 134 includes a connector adapted toconnect to one end region of the dialyzer 110, and the dialyzer outletline 136 includes a connector adapted to connect to another end regionof the dialyzer 110.

Still referring to FIG. 1, the hemodialysis machine 102 includes a touchscreen 118 and a control panel 120. The touch screen 118 and the controlpanel 120 allow the operator to input various different treatmentparameters to the hemodialysis machine 102 and to otherwise control thehemodialysis machine 102. In addition, the touch screen 118 serves as adisplay to convey information to the operator of the hemodialysis system100. A speaker 122 is positioned below the touch screen 118 andfunctions to provide audio signals to the operator of the system 100.Thus, the hemodialysis machine 102 is capable of providing both visualalerts via the touch screen 118 and audio alerts via the speaker 122 tothe operator of the system 100 during use.

The blood component set 104 of the hemodialysis system is secured to amodule 114 attached to the front of the hemodialysis machine 102. Themodule 114 includes a blood pump 116 capable of driving blood throughthe blood circuit. The module 114 also includes various otherinstruments capable of monitoring the blood flowing through the bloodcircuit. The module 114 includes a door 140 that when closed, as shownin FIG. 1, cooperates with the front face of the module 114 to form acompartment sized and shaped to receive the blood component set 104. Inthe closed position, the door 140 presses certain blood components ofthe blood component set 104 against corresponding instruments exposed onthe front face of the module 114. This arrangement facilitates controlof the flow of blood through the blood circuit and monitoring of theblood flowing through the blood circuit.

As depicted in FIG. 1, the hemodialysis system 100 also includes a drainapparatus 200 coupled to the hemodialysis machine 102. The drainapparatus 200 includes a lid 202, an inlet port 204, an outlet port 206,an inlet line 210, an outlet line 212, a drain apparatus pump 214, andan outlet valve 216.

In some implementations, the lid 202 is coupled to the body of the drainapparatus 200 with a hinge. During use, the lid 202 of the drainapparatus 200 may be opened and the venous patient line 108 of the bloodcomponent set 104 may be placed within a chamber of the drain apparatus200 to expel fluid from the venous patient line 108 into the chamber ofthe drain apparatus 200.

The components of the hemodialysis machine 102 and the drain apparatus200 can be disinfected between treatments. For example, a disinfectantfluid can be provided to and circulated through the hydraulic circuit ofthe hemodialysis machine 102 and the drain apparatus 200 betweentreatments in order to disinfect the hemodialysis machine 102 and drainapparatus 200. As described in further detail herein, the drainapparatus 200, when not in use, can be disinfected by closing the lid202 and flowing disinfection fluid through the chamber of the drainapparatus 200.

FIG. 2 depicts a cross section view of the drain apparatus 200 with thelid 202 closed. As depicted in FIG. 2, the drain apparatus includes aninner funnel 218 and an outer funnel 220. The inner funnel 218 forms achamber 208 within the drain apparatus 200 configured to receive andcollect liquid. The outer funnel 220 includes an upper lip 222 thatencompasses an annular surface 224 of the inner funnel 218. The innerfunnel 218 of the drain apparatus 200 is nested within and connected toan outer funnel 220 of the drain apparatus 200. As shown in FIG. 2, theinner funnel 218 is connected to the outer funnel 220 proximate theoutlet port 206 of the drain apparatus 200. The inner funnel 218 can beconnected to the outer funnel 220 by any suitable techniques, such aswelding, injection molding, etc.

The nested arrangement of the inner funnel 218 and the outer funnel 220creates an annular channel 228 between the inner funnel 218 and theouter funnel 220 that surrounds the inner funnel 218. Fluid receivedthrough the inlet port 204 from the inlet line 210 can travel throughthe annular channel 228 between the inner funnel 218 and the outerfunnel 220, over the annular surface 224 of the inner funnel 218, andinto the chamber 208 of the drain apparatus. Arranging the inner funnel218 and outer funnel 220 to create a 360 degree annular channel 228enables fluid to be fairly evenly distributed to the entire surface ofthe chamber 208 of the drain apparatus 200. In some examples, the innerfunnel 218 and outer funnel 220 are arranged to form an annular channel228 with a width of about 0.125 inches to about 0.25 inches.

The inner funnel 218 and the outer funnel 220 of the drain apparatus 200can be formed of any of various different medical grade materials.Examples of such materials include PVC, polyethylene, polypropylene,silicone, polyurethane, high density polyethylene, nylon, ABS, acrylic,isoplast, polyisoprene, polycarbonate, stainless steel, glass, titanium,carbon fiber, and porcelain.

As shown in FIG. 2, a clip 226 is attached to the upper lip 222 of theouter funnel 220. The clip 226 is configured to receive the venouspatient line 108 of the hemodialysis system 100 and to position apatient end of venous patient line 108 within the chamber 208 of thedrain apparatus. As described in the further detail herein, the chamber208 is configured to collect fluids contained within the blood lines andprovide the collected fluids to a drain via the outlet line 212 of thedrain apparatus 200.

Still referring to FIG. 2, the drain apparatus 200 also includes ascreen 236 located within and coupled to the inner funnel 218 of thedrain apparatus 200. The screen 236 is configured to preventparticulates above a defined size from entering, and potentiallyobstructing, the outlet line 212. For example, the screen 236 includes aplurality of openings sized to allow fluid to flow through the screen236 while preventing particulates above a defined size from entering theoutlet line 212. In some examples, the screen 236 includes openings witha diameter of about 0.10 inches to about 0.15 inches (e.g., 0.125 inchdiameter). The screen 236 is positioned in a location within the chamber208 that prevents blood lines positioned within the chamber 208 usingthe clip 226 from contacting the screen 236. In some implementations,the screen 236 is removable and can be removed from the drain apparatus200 for cleaning. The screen 236 can be formed of any of variousdifferent medical grade materials. Examples of such materials includePVC, polyethylene, polypropylene, silicone, polyurethane, high densitypolyethylene, nylon, ABS, acrylic, isoplast, polyisoprene,polycarbonate, stainless steel, titanium, and carbon fiber.

As shown in FIG. 2, the lid 202 of the drain apparatus 200 includes avent 230 with a hydrophobic filter 232. The vent 230 extends through thelid 202 to outside the drain apparatus 200. A coupler 234 is coupled tothe vent 230 to create a fluid seal between the vent 230 and the lid202. The hydrophobic filter 232 is arranged within the vent 230. Asdescribed in further detail herein, as the chamber 208 of the drainapparatus 200 is filled with fluid, air contained within the chamber 208is displaced by the fluid and exits out the vent 230, allowing forcomplete filling of the chamber 208. Further, the hydrophobic filter 232prevents liquids provided to the chamber 208 from exiting through thevent 230. The hydrophobic filter 232 may be made of a hydrophobicmaterial, such as polytetrafluoroethylene (PTFE) (e.g., expandedpolytetrafluoroethylene (ePTFE)), a blend of polyethylene andcarboxymethylcellulose, etc. In certain implementations, the hydrophobicfilter 232 is a fibrous carrier with a matted and woven layer on top ofwhich ePTFE or other micro-porous material is applied. The vent 230 canincludes a plurality of pores, each pore having a diameter of about 15μm to about 45 μm (e.g., 30 μm). In some examples, a material of thevent 230 expands in response to contacting fluid, which closes theplurality of pores in the vent 230 and prevents fluid from passingthrough the vent 230.

Still referring to FIG. 2, the inlet port 204 of the drain apparatus 200is coupled to the inlet line 210. In some implementations, the inletline 210 is coupled to the inlet port 204 using a coupler. The inletline 210 can be coupled to the inlet port 204 using a metal band orplastic band that restricts the tubing of the inlet line 210 around abarb of the inlet port 204. A first end of the inlet line 210 is coupledto the inlet port 204 and a second end of the inlet line 210 is coupledto a fluid line of the hemodialysis machine 102.

In the implementation shown in FIG. 2, a drain apparatus inlet valve 242is fluidly connected to the inlet line and is configured to control theflow of fluids into the chamber 208 via the inlet line 210. The drainapparatus inlet valve 242 can be communicatively coupled to thehemodialysis machine 102 and can be opened and closed in response tosignals received from the hemodialysis machine 102. An example of asuitable valve is a solenoid valve.

The outlet port 206 of the drain apparatus 200 is coupled to the outletline 212. In some implementations, the outlet line 212 is coupled to theoutlet port 206 using a coupler. The outlet line 212 can be coupled tothe outlet port 206 using a metal band or plastic band that restrictsthe tubing of the outlet line 212 around a barb of the outlet port 206.As described in further detail herein, a first end of the outlet line212 is coupled to the outlet port 206 and a second end of the outletline 212 is coupled to a drain line 112 of the hemodialysis machine 102.

The drain apparatus outlet valve 216 is fluidly connected to the outletline 212 of the drain apparatus 200 and is configured to control theflow of fluid from the outlet line 212 to the drain line 112. In someimplementations, the drain apparatus outlet valve 216 is communicativelycoupled to the hemodialysis machine 102 and can be opened and closed inresponse to signals received from the hemodialysis machine 102. Anexample of a suitable valve is a solenoid valve.

As shown in FIG. 2, the drain pump 214 is fluidly coupled to the outletline 212 of the drain apparatus 200. The drain pump 214 is configured topump fluid from the chamber 208 of the drain apparatus 200 through theoutlet line 212 to the drain line 112 of the hemodialysis machine 102.Any of various suitable pumps can be used, such as a peristaltic pump, apiston pump, an impeller pump, a magnetically driven gear pump, etc. Theinlet line 210 and the outlet line 212 of the drain apparatus 200 can beformed of any of various different medical grade materials. Examples ofsuch materials include PVC, polyethylene, polypropylene, silicone,polyurethane, high density polyethylene, nylon, ABS, acrylic, isoplast,polyisoprene, and polycarbonate.

Still referring to FIG. 2, a pressure sensor 240 is coupled to theoutlet line 212 of the drain apparatus 200 proximate the outlet port204. The pressure sensor 240 is configured to measure the fluid pressurein the chamber 208 of the drain apparatus 200. For example, the pressureinside the chamber 208 can be measured by the pressure sensor 240 whilethe chamber 208 is being filled with disinfectant fluid in order todetermine when the chamber 208 is filled with disinfectant fluid basedon the pressure in the chamber 208. In some implementations, thepressure sensor 240 is an inline pressure transducer. Other types ofpressure sensors that can be used include other types of pressuretransducers, such as an M3200 pressure transducer.

FIG. 3 depicts a perspective view of the drain apparatus 200 of FIG. 1with the lid 202 of the drain apparatus 200 in an open position and thevenous patient line 108 attached to the drain apparatus 200 via the clip226. FIG. 4 depicts a perspective view of the drain apparatus 200 withthe lid 202 in the closed position. As depicted in FIGS. 3 and 4, thelid 202 is attached to the outer funnel 220 by a hinge 238 such that thelid 202 can be moved between the open position depicted in FIG. 3 andthe closed position depicted in FIG. 4. The lid 202 forms a seal withthe outer funnel 220 to seal the chamber 208 when in the closed positionto prevent fluids from escaping the top of the chamber 208. The lid 202can be opened or closed based on the process being performed by thehemodialysis machine or the stage of hemodialysis treatment. Forexample, the lid 202 can be opened to receive the venous patient line108 for draining contents of the line 108 into the drain apparatus. Thelid 202 can be closed during disinfection of the drain apparatus 200, asdescribed in further detail herein.

As previously discussed, the dialysate circuit of the hemodialysismachine 102 of FIG. 1 is formed by multiple dialysate components andfluid lines positioned inside the housing of the hemodialysis machine102 as well as the dialyzer 110, the dialyzer inlet line 134, and thedialyzer outlet line 136 that are positioned outside of the housing ofthe hemodialysis machine 102.

FIG. 5 is a schematic showing the flow paths of fluids into, through,and out of the dialysate circuit 500. The dialysate circuit 500 includesa number of dialysate components that are fluidly connected to oneanother via a series of fluid lines and the drain line 112.

Still referring to FIG. 5, a water inlet port 502 is configured toreceive water from an external source and provide the water to a heatexchanger 506 via the fluid line. Heat exchanger 506 is configured towarm the water received by the dialysate circuit 500 through the waterinlet port 502 using the heat of spent dialysate (or other fluid)flowing on an opposite side of the heat exchanger 506.

After exiting the heat exchanger 506, the warmed water flows to thedeaeration and heating chamber 512. The deaeration and heating chamber512 is configured to heat and deaerate water received by the dialysatecircuit 500 through the water port 502. The heating and deaerationchamber 512 includes a temperature control thermistor 514 for monitoringthe temperature of the heated water and a heater 516 to increase thetemperature of the water received by the chamber 512. For example, ifthe temperature of the water received by the deaeration and heatingchamber 512 is below a threshold temperature, as detected by temperaturecontrol thermistor 514, the heater 516 can be used to heat the waterabove the threshold temperature. An aeration orifice 518 is positionedbetween two of the sub-chambers 512C, 512D and is configured deaeratethe flow of water as the deaeration pump 520 pumps the water fromsub-chamber 512A to sub-chamber 512E.

The warmed and deaerated water flows from sub-chamber 512E to mixingchambers 534, 536 where the water, acid concentrate, and bicarbonateconcentrate are mixed. The dialysate circuit 500 includes an acidconcentrate pump 526 coupled to a source of acid concentrate. The acidconcentrate pump 526 is configured to pump acid concentrate into theflow of water travelling from the deaeration and heating chamber 512 tothe mixing chambers 534, 536.

The dialysate circuit 500 also includes a bicarbonate pump 532 that iscoupled to a source of bicarbonate. The bicarbonate pump 532 isconfigured to pump bicarbonate into the flow of water and acidconcentrate between the deaeration and heating chamber 512 and themixing chamber 534, 536.

The mixing chambers 534, 536 are fluidly connected to a fluid linedownstream of the acid concentrate pump 526 and bicarbonate pump 532,and are configured to receive the combined flow of heated water, acidconcentrate, and bicarbonate and mix the fluids to generate a uniformdialysate fluid. As shown in FIG. 5, the mixing chambers 534, 536 arearranged serially to ensure thorough mixing of the dialysate solution.

Balancing devices 554, 556 are fluidly connected to a fluid linedownstream of the mixing chambers 534, 536. The balancing devices 554,556 each include a spherical chamber that is divided into a firstchamber half 558, 560 and a second chamber half 562, 564 by a flexiblemembrane 566, 568. As fluid flows into the first chamber halves 558,560, fluid is forced out of the second chamber halves 562, 564, and viceversa. Valves 538 through 552 are used to control the flow of dialysateinto and out of the balancing devices 554, 556 such that as freshdialysate is flowing into one balancing device 554, spent dialysate isflowing into the other balancing device 556, and vice versa. Forexample, as spent dialysate flows into the second chamber half 562 ofbalancing device 554 and forces fresh dialysate to flow out of firstchamber half 558 of balancing device 554 towards the dialyzer 110, freshdialysate flows into first chamber half 560 of balancing device 556 andforces spent dialysate to flow out of the second chamber half 564 ofbalancing device 556 towards the drain, and vice versa. This alternationof fresh and spent dialysate flowing into the balancing chambers 554,556 is controlled by valves 538 through 552. This balancing deviceconstruction and alternating flow of fresh and spent dialysate helps toensure that the volume of fluid entering the balancing devices 554, 556is equal to the volume of fluid exiting the balancing devices 554, 556.This helps to ensure that the volume of fresh dialysate entering thedialysate circuit is equal to the volume of spent dialysate exiting thedialysate circuit when desired during treatment, as described in greaterdetail below.

During hemodialysis, fresh dialysate passing through the first chamberhalves 558, 560 of the balancing devices 554, 556 is directed to thedialyzer 110 through a dialysate filter 574. Prior to filtration bydialysate filter 574, the fresh dialysate flows through a conductivitycell 570 and a temperature monitor thermistor 572 downstream of the ofthe balancing devices 554, 556. The conductivity cell 570 andtemperature monitor thermistor 572 regulate the temperature of the freshdialysate entering the filter 574 and dialyzer 110. The fresh dialysateflowing out of balancing devices 554, 556 flows along a fluid linethrough the dialysate filter 574, which is configured to filter thefresh dialysate received from the balancing devices 554, 556 prior toproviding the dialysate to the dialyzer 110. One example of such adialysate filter 574 is the DIASAFE®plus dialysis fluid filter availablefrom Fresenius Medical Care filter. During hemodialysis, a bypass valve575 is closed and a dialyzer inlet valve 576 is open in order to directthe flow of dialysate from the dialysis filter 574 to the dialyzer 110.

During hemodialysis, the fresh dialysate flowing out of the firstchamber halves 558, 560 of the balancing devices 554, 556 is directedthrough the dialyzer 110 toward the air separation chamber 593. Spentdialysate exits the dialyzer 110 along a drain line 112 of the dialysatecircuit 500. A pressure sensor 586 located along the drain line 112connecting the dialyzer 110 to the air separation chamber 593 is adaptedto measure the pressure of the spent dialysate exiting the dialyzer 110.Any of various different types of pressure sensors capable of measuringthe pressure of the spent dialysate passing from the dialyzer 110 to theair separation chamber 593 can be used.

The spent dialysate exiting the dialyzer 110 collects in the airseparation chamber 593. The air separation chamber 593 uses an airsensor coupled to the air separation chamber 593 to detect air containedwithin the spent dialysate, and the air separation chamber 593 vents offany air contained with the spent dialysate. Air detected in the spentdialysate by the equalizing chamber travels through the vent valve 594to the drain.

A dialysate flow pump 595 is configured to pump the spent dialysate fromthe air separation chamber 593 through a fluid line to the secondchamber halves 562, 564 of the balancing devices 554, 556. As previouslydiscussed, the flow of spent dialysate into the balancing devices 554,556 is controlled by valves 540 and 544 to alternate the flow of spentdialysate between each of the second chamber halves 562, 564 of thebalancing devices 554, 556.

As one of the second chamber halves 562, 564 of one of the balancingdevices 554, 556 fills with the spent dialysate, fresh dialysate withinthe first chamber half 558, 560 of the respective balancing device 554,556 is expelled towards the dialyzer 110. Subsequently, as the firstchamber half 558, 560 of the respective balancing device 554, 556 isrefilled with fresh dialysate, the spent dialysate is forced out thesecond chamber half 562, 564 of the respective balancing device 554, 556is through one of valves 548, 552, respectively, via drain line 112 tothe drain. As previously discussed, as fresh dialysate is flowing intoone balancing device 554, spent dialysate is flowing into the otherbalancing device 556, and vice versa.

As shown in FIG. 5, an ultrafiltration line 591 is connected to anoutlet of the air separation chamber 593. An ultrafiltration pump 597 isoperatively connected to the ultrafiltration line 591 such that when theultrafiltration pump 597 is operated, spent dialysate can be pulled fromthe air separation chamber 593 and directed to the drain via theultrafiltration line 591. Operation of the ultrafiltration pump 597while simultaneously operating the dialysate flow pump 595 causesincreased vacuum pressure within the line connecting the air separationchamber 593 to the dialyzer 110, and thus creates increased vacuumpressure within the dialyzer 110. As a result of this increased vacuumpressure, additional fluid is pulled from the blood circuit into thedialysate circuit across the semi-permeable structure (e.g.,semi-permeable membrane or semi-permeable microtubes) of the dialyzer110. Thus, the ultrafiltration pump 597 can be operated to remove excessfluid from the patient.

As shown in FIG. 5, the inlet line 210 of the drain apparatus isconnected to a fluid line of the dialysate circuit downstream of thedialysate filter 574 and upstream of the dialyzer 110. The dialyzerinlet valve 576 along a fluid line downstream of the dialysate filter574 can be closed in order to direct flow of fluid exiting the dialysatefilter 574 to the inlet line 210 and chamber 208 of the drain apparatus200.

Still referring to FIG. 5, the outlet line 212 of the drain apparatus200 is coupled to drain line 112 downstream of the drain valve 589 ofthe drain line 112. As previously discussed, a drain apparatus outletvalve 216 is positioned along the outlet line 212. When the valve 216 isclosed, fluid provided to the chamber 208 through the inlet line 210collects in the chamber 208 of the drain apparatus 200. In someexamples, fluid is continuously provided from a fluid line of thedialysate circuit 500 to the drain apparatus 200 via the inlet line 210until the pressure sensor 240 positioned along the outlet line 212detects a pressure in the chamber 208 of the drain apparatus 200indicating that the chamber 208 is full of fluid. Opening the valve 216allows fluid collected in the chamber 208 of the drain apparatus 200 toflow through the outlet line 212 to the drain line 112. For example,after a heated disinfectant fluid provided to the chamber 208 via theinlet line 210 has been allowed to dwell in the chamber 208 for apredetermined amount of time, the valve 216 can be opened to drain thedisinfectant fluid from the chamber 208 to the drain line 112. The drainapparatus pump 214 positioned along the outlet line 212 can also be usedto pump fluid from the chamber 208 of the drain apparatus 200 to thedrain line 112 via the outlet line 212.

The various fluid lines and drain line 112 of the dialysate circuit 500,as well as the lines 210 and 212, can be formed of any of variousdifferent medical grade materials. Examples of such materials includePVC, polyethylene, polypropylene, silicone, polyurethane, high densitypolyethylene, nylon, ABS, acrylic, isoplast, polyisoprene, andpolycarbonate.

FIG. 6 is a schematic showing the flow paths of fluids into, through,and out of the blood circuit 600 of the hemodialysis system 100. Duringhemodialysis treatment, one end 628 of the arterial patient line 106 isfluidly connected to an artery of a patient 602. The arterial patientline 106 is also fluidly connected to an arterial pressure sensor 604.Arterial pressure sensor 604 is fluidly connected to the arterialpatient line 106 and is configured to measure the pressure of the bloodflowing the arterial patient line 106. As shown in FIG. 6, the arterialpressure sensor 604 is positioned upstream of the blood pump 116 tomeasure a pre-pump arterial pressure. Upon detecting that the pressurewithin the blood circuit 600 has dropped below a certain level, thearterial pressure sensor 604 can transmit a signal to that effect to thehemodialysis machine 102, which can activate an audio and/or visualalarm to alert the operator of the system of a drop in blood pressure ofthe patient 602. In some implementations, the arterial pressure sensor604 is provided as combination of a pressure transducer aligned with apressure sensor capsule. For example, a pressure transducer may bepositioned on a door 140 of the module 114 such that when the door 140is closed, the pressure transducer presses against the pressure capsuleand can measure the pressure of blood flowing through the capsule. Forexample, as the fluid pressure changes within the pressure sensorcapsule, the amount of pressure applied to the pressure transducer bythe pressure sensor capsule also changes.

The arterial patient line 106 extends from the patient 602 to a firstpump line adaptor 618, which connects the arterial patient line 106 toone end of a U-shaped pump line 620. The other end of the pump line 620is connected to a second pump line adaptor 622, which is fluidlyconnected to a dialyzer inlet line 134. The dialyzer inlet line 134 isconnected via a tube adaptor to a blood entry port 624 of the dialyzer110. A blood exit port 626 of the dialyzer 110 is connected to anothertube adaptor, which connects the dialyzer 110 to a dialyzer outlet line136. The blood pump 116 pumps blood from the artery of the patient 602through the arterial patient line 106 to the dialyzer 110.

A venous pressure sensor 606 is positioned along a dialyzer outlet line136, upstream of an air release device 608 and is configured to monitorblood pressure on the venous side of the dialyzer 110. In someimplementations, the venous pressure sensor 606 is provided ascombination of a pressure transducer aligned with a pressure sensorcapsule. For example, a pressure transducer may be positioned on a door140 of the module 114 such that when the door 140 is closed, thepressure transducer presses against the pressure capsule and canmeasures the pressure of blood flowing through the capsule. For example,as the fluid pressure changes within the pressure sensor capsule, theamount of pressure applied to the pressure transducer by the pressuresensor capsule also changes.

As shown in FIG. 6, the dialyzer outlet line 136 is coupled to an airrelease device 608. The air release device 608 includes a vent assembly610 located at the top of the air release device 608. The vent assembly610 allows air to pass therethrough while inhibiting (e.g., preventing)liquid from passing therethrough. If blood passing through the bloodcircuit 600 during treatment contains air, the air will be vented to theatmosphere as the blood passes through the air release device 608.

In some implementations, the module 114 of the hemodialysis machine 102includes a level detector 612 that aligns with the air release device608 when the blood component set 104 is secured to the front face of themodule 114. The level detector 612 is adapted to detect the level ofliquid (e.g., blood and/or saline) within the air release device 608.

Still referring to FIG. 6, a venous patient line 108 is connected to anexit port of the air release device 608 at a first end and is fluidlyconnected to a vein of a patient 602 during treatment at a second end630.

An air bubble detector 632 is positioned along the venous patient line108 downstream of the air release device 608. The air bubble detector632 is capable of detecting air bubbles within the venous patient line108. The air bubble detector 632 includes a housing that forms a channelin which the venous patient line 108 is received. In someimplementations, the door 140 of the module 114 of the hemodialysismachine 102 includes a fin that presses the venous patient line 108 intothe channel of the housing and against a sensor of the air bubbledetector 632 when the door 140 is closed.

An occluder 634 is positioned along the venous patient line 108downstream of the air bubble detector 632. The occluder 634 isconfigured to crimp the portion of the venous patient line 108 disposedtherein to prevent blood from passing through the venous patient line108 when activated. The occluder 634 can, for example, be connected tothe air bubble detector 632 so that the occluder 634 can be activatedwhen the air bubble detector 632 detects an air bubble within the venouspatient line 108. Such an arrangement helps to ensure that no airbubbles reach the patient in the event that the air release device 608fails to remove one or more air bubbles from the blood. Similar to theair bubble detector 632, the occluder 634 includes a housing that formsa channel in which the venous patient line 108 is received. In someimplementations, the door 140 of the module 114 includes a fin thatpresses the venous patient line 108 into the channel of the housing ofthe occluder 634 when the door 140 is closed.

In addition to the blood lines forming the main blood circuit 600, asaline delivery line 126 and a drug delivery line 128 can be connectedto the blood circuit 600 for the introduction of saline and drugs (e.g.,heparin), respectively, into the blood circuit 600. As depicted in FIG.6, the saline delivery line 126 is connected at a first end to a salinebag 138 and at a second end to the first pump line adaptor 618.

The drug delivery line 128 is connected at a first end to a syringe 130,which can contain a drug to be provided to the patient 602, and at asecond end to the second pump line adaptor 622. The syringe 130 may becoupled to a drug pump 132. The drug pump 132 is a syringe pump thatincludes a clamping mechanism configured to retain the syringe 130 ofthe blood component set 104. The drug pump 132 also includes a steppermotor configured to move the plunger of the syringe 130 along the axisof the syringe 130. A shaft of the stepper motor is secured to theplunger in a manner such that when the stepper motor is operated in afirst direction, the shaft forces the plunger into the syringe 130, andwhen operated in a second direction, the shaft pulls the plunger out ofthe syringe 130. The drug pump 132 can thus be used to inject a liquiddrug (e.g., heparin) from the syringe 130 into the blood circuit 600 viathe drug delivery line 128 during use, or to draw liquid from the bloodcircuit 600 into the syringe 130 via the drug delivery line 128 duringuse.

The various blood lines, the saline delivery line 126, and the drugdelivery line 128 can be formed of any of various different medicalgrade materials. Examples of such materials include PVC, polyethylene,polypropylene, silicone, polyurethane, high density polyethylene, nylon,ABS, acrylic, isoplast, polyisoprene, and polycarbonate.

The various blood lines, the saline delivery line 126, and the drugdelivery line 128 are typically retained within the module 114. Varioustechniques can be used to secure the lines to the module 114. Forexample, a carrier body with a series of apertures and recesses forcapturing and retaining the various blood lines and components can besecured to the module 114 of the hemodialysis machine 102. In someexamples, mechanical attachment devices (e.g., clips or clamps) can beattached to a carrier body and used to retain the lines, and the carrierbody can be attached to the module 114 of the hemodialysis machine 102.As another example, the lines can be adhered to or thermally bonded to acarrier body, and the carrier body can be attached to the module 114 ofthe hemodialysis machine.

Referring to FIGS. 5 and 16, a method of preparing the hemodialysissystem 100 for hemodialysis treatment will now be described. Beforehemodialysis treatment is initiated, the blood component set 104 isconnected to the hemodialysis machine 102, as shown in FIG. 1. Forexample, a first end of the arterial patient line 106 is attached to thepump line 620 via the first pump line adaptor 618 and a first end of thevenous patient line 108 is attached to an exit port of the air releasedevice 608. Further, as depicted in FIG. 16, before priming thehemodialysis system 100, a patient end 628 of the arterial patient line106 is coupled to the saline bag 138 via the saline delivery line 126and a patient end 630 of the venous patient line 108 is attached to thedrain apparatus 200 using the clip 226 of the drain apparatus. Byattaching the venous patient line 108 to the drain apparatus 200 usingthe clip 226, the patient end 630 of the venous patient line 108 can bepositioned within the chamber 208 of the drain apparatus 200 withouttouching the walls of the inner funnel 218 of the drain apparatus 200

To begin priming the system 100, saline is introduced from the salinebag 138 into the blood circuit 600 via the arterial patient line 106. Todraw the saline from the saline bag 138 through the arterial patientline 106 and into the blood circuit 600, the blood pump 132 is turnedon. The blood pump 132 draws the saline from the saline bag 138, throughsaline delivery line 126 and the arterial patient line 106, through thearterial pressure sensor 604, and through the pump line 602 towards thedialyzer 110. The saline flows into the dialyzer 110 via the dialyzerinlet line 134 and exits the dialyzer 110 via the dialyzer outlet line136. As the saline flows through the dialyzer outlet line 136 towardsthe air release device 608, the saline passes through the venouspressure sensor 606.

Next, the saline flows through an entry port of the air release device608 and fills the air release device 608. To fill the air release device608, the venous patient line 108, which leads away from the air releasedevice 608, is clamped while the saline is forced into the air releasedevice 608. Air is forced out the top of the air release device 608 andthrough the vent assembly 610 as saline fills the air release device.Because the venous patient line 108 is still clamped at this time, theoperation of the blood pump 116 builds a substantial amount of pressurewithin the blood air release device 608 via the vent assembly 610 of theair release device 608. The saline does not pass through the ventassembly 610 because the membrane of the vent assembly 610 ishydrophobic.

Once the air release device 608 is filled with saline, the clamp isremoved from the venous patient line 108 and saline flows through thevenous patient line 108 towards the patient end 630 of the venouspatient line 108. Once the entire blood circuit 600 is filled withsaline, any additional (e.g., excess) saline pumped through the bloodcomponent set 104 exits the patient end 630 of the venous patient line108 and is captured by the chamber 208 of the drain apparatus 200. Thedrain apparatus outlet valve 216 fluidly connected to the outlet line212 of the drain apparatus 200 is open and the drain apparatus pump 214is turned on during priming to draw saline collected from the venouspatient line 108 by the drain apparatus 200 to the drain line 112 viathe outlet line 212.

The process of priming described above functions to remove air fromwithin the blood circuit 600 and fills the blood circuit 600 with salinefrom the patient end 628 of the arterial patient line 106 to the patientend 630 of the venous patient line 108. Once all air is out of thepatient lines 106, 108 and the blood circuit 600 is filled with saline,clamps are closed on the patient ends 628, 630 of the patient lines 106,108. Once clamped, the patient end 628 of the arterial patient line 106is removed from the saline bag 138 and the patient end 630 of the venouspatient line 108 is removed from the drain apparatus 200.

After the initial priming, the patient ends 628, 630 of the patientlines 106, 108 can be connected together using a sterile recirculationconnector and the saline contained within the blood circuit 600 can berecirculated through the blood circuit 600 away from the drain apparatus200 until the patient 602 is ready for treatment.

Once the blood circuit 600 has been primed and the patient 602 is readyfor treatment, the patient ends 628, 630 of the arterial and venouspatient lines 106, 108 are connected to a patient 602, as shown in FIG.6, and hemodialysis is initiated. Referring to FIGS. 5 and 6, a methodof performing dialysis treatment using the hemodialysis system 100 willnow be described.

During hemodialysis, blood is circulated through the blood circuit(i.e., the various blood lines and blood components, including thedialyzer 110, of the blood component set 104). At the same time,dialysate is circulated through the dialysate circuit (i.e., the variousfluid lines and dialysate components, including the dialyzer 110).

As shown in FIG. 5, dialysate is generated by the dialysate circuit 500and provided to the dialyzer 110 via fluid line of the dialysate circuit500. For example, referring to FIG. 5, during hemodialysis,recirculation valve 508 is closed and water inlet valve 510 is open, andwater used for generating dialysate is received by the hydraulic circuit500 through the water inlet port 502. The water passes through the heatexchanger 506, the open water inlet valve 510, and into the heating anddeaeration chamber 512. In some implementations, if the temperature ofthe water as detected by temperature control thermistor 514 of theheating sub-chamber 512A is below a threshold temperature, a heater 516in heating sub-chamber 512B can be used to heat the water above thethreshold temperature. The heated water passes through an aerationorifice 518 positioned between sub-chambers 512C, 512D to deaerate theflow of water.

During hemodialysis, the deaeration pump 520 pumps the flow of heatedand deaerated water from deaeration and heating chambers 512 to themixing chambers 534, 536 via a fluid line. The flow of heated anddeaerated water combines with a flow of acid concentrate provided by theacid concentrate pump 526 and a flow of bicarbonate provided by thebicarbonate pump 532. As shown in FIG. 5, the acid concentrate can befiltered by acid concentrate filter 524 prior to introduction of theconcentrate into the flow of heated water. Similarly, bicarbonateprovided by bicarbonate pump 532 can be filtered by bicarbonate filter530 prior to introduction of the bicarbonate into the flow of heatedwater. The mixing chambers 534, 536 receive the combined flow of heatedwater, acid concentrate, and bicarbonate and mix the fluids to generatea uniform dialysate fluid.

As previously discussed, the dialysate flows from mixing chamber 536 tothe first chamber half 558, 560 of one of the balancing devices 554, 556as controlled by valves 538 and 542, respectively. As previouslydiscussed, as fresh dialysate is flowing into one balancing device 554,spent dialysate is flowing into the other balancing device 556, and viceversa. As fresh dialysate flows into a first chamber halves 558, 560,spent dialysate is forced out the respective second chamber halves 562,564 through valves 548, 552 via drain line 112. Additionally, as spentdialysate flows into the second chamber halves 562, 564 from dialyzer110 via the air separation chamber 593, the fresh dialysate in therespective first chamber halves 558, 560 is forced out the respectivebalancing devices 554, 556 through valves 546, 550, respectively,towards the dialyzer 110.

Before the dialysate generated by the dialysate circuit 500 is providedto the dialyzer 110, the dialysate passes through the dialysate filter574 to remove any potential impurities in the dialysate. Duringhemodialysis, bypass valve 575 is closed and dialyzer inlet valve 576 isopen to direct flow of dialysate from the dialysis filter 574 to thedialyzer 110, and dialysate flows from the dialysate filter 574 to thedialyzer 110. In addition, during hemodialysis, drain apparatus inletvalve 242 is closed to prevent dialysate from flowing into the drainapparatus during dialysis. If, during hemodialysis, pressure transducer240 detects a build-up of fluid in the drain apparatus 200 for anyreason (e.g., malfunction of valve 242), control valve 216 can be openedto empty the drain apparatus without interrupting the hemodialysis. Insome implementations, the dialysate flows through a dialysate flow lineindicator 578 prior to entering the dialyzer 110.

During hemodialysis, spent dialysate exits the dialyzer 110 and passesthrough the dialysate circuit via the drain line 112. As depicted inFIG. 5, during hemodialysis, the dialyzer outlet valve 584 is open andspent dialysate is received from the dialyzer 110 by the drain line 112and passes through a fluid line filter 582 and dialyzer outlet valve584. Fluid line filter 582 filters the spent dialysate exiting thedialyzer 110. The spent dialysate exiting the dialyzer 110 passesthrough a pressure sensor 586 configured to measure the pressure ofdialysate entering the drain line 112 from the dialyzer 110 and passesthrough a blood leak detector 588 configured to detect whether blood hasleaked into the dialysate across the dialyzer 110 membrane.

Before entering the air separation chamber 593, the spent dialysateflows through a post-dialyzer temperature thermistor 590 and apost-dialyzer conductivity cell 592 configured to regulate thetemperature of the spent dialysate.

As previously discussed, the spent dialysate is received by the airseparation chamber 593, which is configured to vent off any aircontained in the dialysate through valve 594. The dialysate flow pump595 draws dialysate from the air separation chamber 593, through a draincheck valve 596, and into one of the second chamber halves 562, 564 ofthe balancing devices 554, 556 through one of valves 540 and 544,respectively. Drain check valve 596 is fluidly coupled to the drain line112 downstream of the dialysate flow pump 595 and is configured toprevent fluid from flowing backwards along the drain line 112 towardsthe dialysate flow pump 595.

As fresh dialysate is provided to one of the first chamber halves 558,560 of the balancing devices 554, 556, the spent dialysate in therespective second chamber half is forced out the respective balancingdevice 554, 556 along the drain line 112 to the heat exchanger 506.

During hemodialysis, the ultrafiltration pump 597 operatessimultaneously with the dialysate flow pump 595 to generate an increasedvacuum pressure within the drain line 112 connecting the air separationchamber 593 to the dialyzer 110, and thus creates increased vacuumpressure within the dialyzer 110. As a result of this increased vacuumpressure, additional fluid is pulled from the blood circuit 600 into thedialysate circuit 500 across the semi-permeable structure (e.g.,semi-permeable membrane or semi-permeable microtubes) of the dialyzer110. This additional fluid is passed along the drain line 112 through anultrafiltration pump filter 598 downstream of the air separation chamber593 and through an ultrafiltration check valve 599, and to the drainline 112 and the heater. The ultrafiltration check valve 599 preventsfluid from flowing backwards along the ultrafiltration line 591 towardsthe ultrafiltration pump 597.

After passing through the heat exchanger 506, spent dialysate exits thedialysate circuit through the drain line 112 and travels to a drainoutside the hemodialysis machine 102.

Referring to FIG. 6, during hemodialysis, the patient's 602 blood isdrawn from the patient end 628 of the arterial patient line 106 into theblood circuit 600 by the blood pump 116. In some implementations, priorto providing the patient's 602 blood the dialyzer 110, the flow of bloodis combined with saline provided by saline delivery line 126 and one ormore drugs (e.g., heparin) provided from syringe 130 by drug pump 132through the drug delivery line 128. The combined flow enters thedialyzer 110 through dialyzer inlet line 134.

After passing through the dialyzer 110, the patient's 602 filtered bloodexits the dialyzer 110 and enters the blood circuit 600 through thedialyzer outlet line 136. The blood flows through the venous pressuresensor 606 to the air release device 608. As previously discussed, theair release device 608 removes any air contained within the filteredblood through the vent assemble 610.

After flowing through the air release device 608, the deaerated,filtered blood flows through the venous patient line 108 to an airbubble detector 632. As previously discussed, the air bubble detector isconfigured to detect air bubbles contained in the flow of blood. Afterpassing through the air bubble detector 632, the filtered blood passesthrough an occluder 634. As previously discussed, the occluder 634 can,for example, be connected to the air bubble detector 632 so that theoccluder 634 can be activated when the air bubble detector 632 detectsan air bubble within the venous patient line 108. If no air bubbles aredetected by the air bubble detector 632, the blood flows through theoccluder 634 to the patient end 630 of the venous patient line 108, andinto the patient.

After the dialysis treatment has been performed, blood contained withinthe blood circuit 600 is reinfused (i.e. rinsed back) to the patient602. To perform reinfusion, the arterial patient line 106 is clamped,and the patient end 628 of the arterial patient line 106 is attached tothe saline bag 138. The arterial patient line 106 is then unclamped, andsaline is pumped from the saline bag 138 through the arterial patientline 106 by the blood pump 116. The saline is then pumped throughout theentire blood circuit 600 to the patient end 630 of the venous patientline 108 to push any blood remaining in the blood circuit 600 back tothe patient 602 and fill the circuit 600 with saline.

Once a desired amount of the blood contained within the blood circuit600 has been reinfused back to the patient 602, the patient lines 106,108 are clamped and the venous patient line 108 is removed from thepatient 602. As depicted in FIG. 16, the patient end 630 of the venouspatient line 108 is attached to the drain apparatus 200 using the clip226. By attaching the venous patient line 108 to the drain apparatus 200using the clip 226, the patient end 630 of the venous patient line 108is positioned within the chamber 208 of the drain apparatus 200 withouttouching the walls of the inner funnel 218. The blood pump 132 draws thesaline from the saline bag 138 through the arterial patient line 106 andcirculates the saline throughout all components of the blood circuit600. After circulating through the blood circuit 600, the saline exitsthe patient end 630 of the venous patient line 108 and collects in thechamber 208 of the drain apparatus 200. The drain apparatus outlet valve216 is open and the drain apparatus pump 214 is turned on to draw thesaline collected from the venous patient line 108 by the drain apparatus200 to the drain line 112 via the outlet line 212. Saline iscontinuously pumped through the blood circuit 600 until all remainingpatient fluids have been flushed from the blood circuit 600 into thedrain apparatus 200. In some cases, for example, saline is pumpedthrough the blood circuit 600 until the saline bag 138 is empty.

After completing the patient's treatment and flushing the blood circuit600, the blood component set 104 is disconnected from the module 114 ofthe hemodialysis machine 102 and discarded. Dialysate contained withinthe dialysate circuit is pumped to a drain outside the hemodialysismachine via the drain line 112 using the dialysate flow pump 212 and/orthe ultrafiltration pump 214. Following treatment, the dialysate circuitand drain apparatus are disinfected in preparation for a subsequenttreatment.

Referring to FIGS. 2 and 5, a method of disinfecting the dialysatecircuit 500 and drain apparatus 200 will now be described. As previouslydiscussed, after completing dialysis treatment and flushing the bloodcircuit 600, the venous patient line 108 is removed from the drainapparatus 200 and discarded with the rest of the blood component set104. In some implementations, during disinfection, one or more of theacid concentrate port 522 and bicarbonate port 528 of the dialysatecircuit are removed from the acid concentrate and bicarbonate sourcesand are connected to a source of chemical disinfectant fluidconcentrate. Prior to disinfection of the dialysate circuit 500 and thedrain apparatus 200, the lid 202 of the drain apparatus 200 is closed toform a liquid-tight seal with the chamber 208 of the drain apparatus 200and the drain apparatus outlet valve 216 on the outlet line 212 isclosed.

Once the lid 202 of the drain apparatus is closed and the drainapparatus outlet valve 216 is closed, sterilization of the dialysatecircuit 500 and drain apparatus 200 may begin. To disinfect thedialysate circuit 500 and drain apparatus 200, water is pumped into thedialysate circuit 200 from the water inlet port 502 to the heatexchanger 506.

Water heated by heat exchanger 506 flows from the heat exchanger 506through the recirculation valve 508 to the heating and deaerationchamber 512. The deaeration and heating chamber 512 is configured toheat and deaerate water received by the dialysate circuit 500 throughthe water port 502 for disinfection. The water is heated to a desiredtemperature in the heating and deaeration chamber 512.

One or more of the acid concentrate pump 526 and the bicarbonate pump532 pump chemical disinfectant concentrate into the flow of heated waterexiting the heating and deaeration chamber 512. The combined flow ofheated water and chemical disinfectant concentrate are provided to themixing chambers 534, 536 to mix the heated water and disinfectantconcentrate to create a homogenous disinfectant fluid.

Disinfectant fluid exits mixing chamber 536 and flows through valves 538and 542 to the one of the first chamber halves 558, 560 of the one ofthe balancing devices 554, 556. As with the flow dialysate solution, asdisinfectant fluid flows through the first chamber half 558 of onebalancing device 554, disinfectant fluid flows into the second chamberhalf 564 of the other balancing device 556, and vice versa, ascontrolled by valves 538 through 552. Further, as with the flow ofdialysate solution, as disinfectant fluid flows into the first chamberhalves 558, 560 of the balancing devices 554, 556, disinfectant fluid issimultaneously forced out of the second chamber halves 562, 564, andvice versa.

The disinfectant fluid flowing out of the first chamber halves 558, 560of the balancing devices 554, 556 flows through a conductivity cell 570and a temperature monitor thermistor 572 towards the dialysate filter574. During the initial flow of disinfectant fluid through the dialysatecircuit 500, the bypass valve 575 is open and the drain apparatus inletvalve 242 and the vent valve 594 are closed to direct disinfectant fluidfrom the dialysate filter 574 towards the post-dialyzer temperaturethermistor 590 and the post-dialyzer conductivity cell 592 and throughthe air separation chamber 593.

Disinfectant fluid is then pumped from the air separation chamber 593 toone of the second chamber halves 562, 564 of one of the balancingdevices 554, 556 through valves 540 and 544, respectively, by one ormore of the dialysate flow pump 595 and the ultrafiltration pump 597. Asdisinfectant fluid flows into the first chamber halves 558, 560, thedisinfectant fluid in the second chamber halves 562, 564 flows out ofthe second chamber halves 562, 564 through valves 548, 552, respectivelyvia the drain line 112. During disinfection, the drain valve 589 isclosed, and disinfectant fluid exiting second chamber halves 562, 564flows through the drain line 112 to the heat exchanger 506 and then backdown through recirculation valve 508 via a fluid line.

Water is continuously added the dialysate circuit 500 via water inletport 502 in order to produce disinfectant fluid to circulate throughoutthe entire dialysate circuit 500. During disinfection, water inletpressure regulator 504 monitors the fluid pressure of the fluid lineextending from the water inlet 502, and whenever the water inletpressure regulator 504 detects that a threshold pressure indicating theentire dialysate circuit is filled with disinfectant fluid has beenreached, bypass valve 575 is closed and drain apparatus inlet valve 242is opened. By closing bypass valve 575 and opening drain apparatus inletvalve 242, disinfectant fluid exiting the dialysate filter 574 isdirected to the drain apparatus 200 via the inlet line 210 coupled tothe outlet of the dialysate filter 574.

Still referring to FIGS. 2 and 5, disinfectant fluid flows through theopen drain apparatus inlet valve 242 and the inlet line 210 to the inletport 204 of the drain apparatus 200, and flows up into and fills theannular channel 228 between the inner funnel 218 and outer funnel 220.Once the disinfectant fluid reaches the top of the annular channel 228,the curved upper lip 222 of the outer funnel 220 forces the solutionover the annular surface 224 of the inner funnel 218, causing thedisinfectant fluid to run down the surface of the inner funnel 218.Because the annular channel 228 completely surrounds the inner funnel,the disinfectant fluid is evenly distributed across the surface of theinner funnel 218 and washes the entire surface of the inner funnel 218.

During this portion of the disinfection, the drain apparatus outletvalve 216 is closed to allow the chamber 208 of the drain apparatus 200to be filled with disinfectant fluid. In addition, during this portionof disinfection, the pump 214 is in a position to prevent disinfectantfluid from flowing to the drain line 112 via the outlet line 212 inorder to allow the chamber 208 of the drain apparatus 200 to be filledwith disinfectant fluid. As disinfectant fluid enters the chamber 208 ofthe drain apparatus 200 via the inlet line 210 and annular channel 228,the chamber 208 begins to fill with disinfectant fluid and any air inthe chamber 208 exits out the vent 230 and hydrophobic filter 232coupled to the closed lid 202 of the drain apparatus 200. Thehydrophobic filter 232 attached to and covering the vent 230 preventsdisinfectant fluid from passing through the vent 232. This arrangementof the vent 230 and hydrophobic filter 232 allows substantially all ofthe air in the chamber 208 to be displaced by disinfectant fluid,allowing for almost the entire chamber 208 of the drain apparatus 200 tobe filled with disinfectant fluid when the outlet valve 216 is closed.

The pressure sensor 240 coupled to the outlet line 212 of the drainapparatus 200 monitors the fluid pressure in the chamber 208 duringdisinfection. Once the pressure sensor 240 detects that the pressure inthe chamber 208 has reached a threshold pressure indicating that thechamber 208 is filled with fluid, drain apparatus inlet valve 242 isclosed to prevent any additional disinfectant fluid from entering thechamber 208 via the inlet line 210. In some implementations, once thepressure sensor 240 detects that the pressure in the chamber 208 hasreached a threshold pressure indicating that the chamber 208 is filledwith fluid, a signal is sent to close the water inlet valve 510 in orderto prevent additional water from being added to the dialysis circuit 500via the water inlet port 502 and stop the production of disinfectantfluid.

Once the chamber 208 is full of disinfectant fluid, the drain apparatusoutlet valve 216 remains closed for a predetermined amount of time toallow the disinfectant fluid to dwell in the chamber 208 for apredetermined amount of time. In some implementations, the disinfectantfluid dwells in the chamber 208 for at least 10 minutes (e.g. at least30 minutes, 10 minutes to 60 minutes).

After the disinfectant fluid has dwelled in the chamber 208 for thepredetermined amount of time, the drain apparatus outlet valve 216 isopened. The drain apparatus pump 214 draws the disinfectant fluid out ofthe chamber 208 through outlet port 206 and the open drain apparatusoutlet valve 216 to the drain line 112 via the outlet line 212. Thedrain apparatus pump 214 continues to run until all of the disinfectantfluid is pumped out of the drain apparatus 200 to the drain line 112.

Similarly, once the disinfectant fluid has recirculated through thedialysate circuit for a predetermined amount of time, the recirculationvalve 508 is closed and the drain valve 589 is opened to direct thedisinfectant fluid through the drain line 112 towards a drain. In someimplementations, the dialysate flow circuit pumps the disinfectant fluidthrough the balancing devices 554, 556 and along the drain line 112through drain valve 589. In some implementations, the drain valve 589and the drain apparatus outlet valve 216 are opened at or near the sametime, and the dialysate circuit 500 and drain apparatus 200 are drainedof disinfectant fluid simultaneously.

While certain embodiments have been described above, other embodimentsare possible.

FIG. 7, for example, is a schematic showing an alternate arrangement ofthe dialysate circuit 500 and the drain apparatus 200 of thehemodialysis machine 102. As shown in FIG. 7, the drain apparatus 200does not include a drain apparatus pump (e.g. drain apparatus pump 214of FIGS. 2-5) along the outlet line 212 between the outlet port 206 ofthe drain apparatus 200 and the drain line 112. In such instances, drainapparatus 200 is configured such that the fluid contained within thechamber 208 of the drain apparatus 200 is gravity drained to the drainline 112 via the outlet line 212 whenever the drain apparatus valve 216is open. For example, during disinfection of the drain apparatus 200,disinfectant fluid contained in the chamber 208 of the drain apparatus200 drains through the outlet line 212 to the drain line 112 by gravitywhenever the drain apparatus outlet valve 216 is opened.

In some embodiments, the drain apparatus includes a drain pump along theoutlet line 210 (such as drain pump 214), but does not include a drainvalve (e.g., drain valve 216 of FIGS. 2-5, 7) along the outlet line 212between the outlet port 206 of the drain apparatus 200 and the drainline 112. In such instances, drain pump 214 acts to control the flow offluid out of the chamber 208 via the outlet line 212. For example,during disinfection of the drain apparatus 200, the drain pump 214 canbe configured to block fluid from flowing through the outlet line 212 tothe drain until the pump 214 is activated to pump the fluid from thechamber 208 to the drain line 112 via the outlet line 212.

FIG. 8 is a schematic showing an alternate arrangement of the dialysatecircuit 500 and drain apparatus 200 of the hemodialysis machine 102. Asshown in FIG. 8, the inlet line 210 of the drain apparatus 200 isfluidly connected to the fluid line downstream of the dialysate filter574 and the outlet line 212 of the drain apparatus 200 is fluidlyconnected to a portion of the drain line 112 of the dialysate circuit500 upstream of the dialysate flow pump 595. In this arrangement, asdepicted in FIG. 8, the drain apparatus 200 does not include a drainapparatus pump (e.g. drain apparatus pump 214 of FIGS. 2-5) along theoutlet line 212. Instead, the negative pressure created by dialysateflow pump 595 of the dialysate circuit 500 is used to draw fluidcontained within the chamber 208 of the drain apparatus 200 out of thedrain apparatus 200 through the drain apparatus outlet valve 216 via theoutlet line 212. Using this arrangement, fluid contained within thechamber 208 of the drain apparatus 200 is drained through the outletline 212 and provided to the dialysate circuit 500 downstream of the airseparation chamber 593. The dialysate flow pump 595 is then used to pumpthe fluid away from the drain apparatus 200 through the drain line 112to one of the second chamber halves 562, 564 of one of the balancingdevices 554, 556 and on to the drain, as described above. For example,using this arrangement during disinfection of the drain apparatus 200,the drain apparatus outlet valve 216 is open and the dialysate flow pump595 draws the disinfectant fluid contained in the chamber 208 of thedrain apparatus 200 through the outlet line 212 to a portion of thedrain line 112 of the dialysate circuit 500 downstream of the airseparation chamber 593. The dialysate flow pump 595 then flows thedisinfectant fluid to one of the second chamber halves 562, 564 of oneof the balancing devices 554, 556 via the drain line 112. Finally, thedisinfectant fluid exits the second chamber halves 562, 564 of thebalancing devices 554, 556 and flows to a drain via the drain line 112.

Similarly, in some implementations, the outlet line 212 of the drainapparatus 200 can be fluidly connected to a portion of the drain line112 of the dialysate circuit 500 upstream of the ultrafiltration pump597 of the dialysate circuit. In this arrangement, negative pressurecreated by ultrafiltration pump 597 of the dialysate circuit 500 is usedto draw fluid contained within the chamber 208 of the drain apparatus200 out of the drain apparatus 200 through the drain apparatus outletvalve 216 via the outlet line 212. The ultrafiltration pump 597 is thenused to pump the fluid away from the drain apparatus 200 through thedrain line 112 to one of the second chamber halves 562, 564 of the oneof balancing devices 554, 556 and on to the drain, as described above.

Additionally, while the inlet line 210 of the drain apparatus 200 hasbeen described as being fluidly connected to the fluid line 108downstream of the dialysate filter 574, the inlet line 210 canalternatively be coupled to a fluid line of the dialysate circuit 500 atany other point within the dialysate circuit 500 upstream of thedialyzer 110.

While the drain apparatus 200 is described as having a vent 230 andhydrophobic filter 232 to allow for complete filling of the chamber 208of the drain apparatus 200, other configurations of the drain apparatusmay alternatively be provided to allow for complete filling of thechamber 208. FIGS. 9-14 depict cross-section views of alternate drainapparatuses for the hemodialysis system of FIG. 1.

As depicted in FIG. 9, in some implementations, rather than having avent and hydrophobic filter (e.g., vent 230 and hydrophobic filter 232of FIG. 2), the lid 902 of the drain apparatus can include a pluralityof vents or holes 924 through the lid 902. In this arrangement, the lid902 of the drain apparatus 900 is liquid-tight when closed and fluidcontained within the chamber 208 of the drain apparatus can exit throughthe holes 924 in the lid 902. This arrangement of the holes 924 in thelid 902 of the drain apparatus 900 allows all of the air in the chamber208 of the apparatus 900 to be displaced by disinfectant fluid duringdisinfection, allowing for the entire chamber 208 to be filled withdisinfectant fluid when the outlet valve 216 is closed. In someimplementations, in order to fill the chamber 208 of the drain apparatus900 with disinfectant fluid during disinfection, a pressure sensor 240coupled to the outlet line 212 monitors the fluid pressure in thechamber 208 of the drain apparatus 900 during disinfection, and once thepressure sensor 240 detects that the pressure in the chamber 208 hasreached a threshold pressure indicating that the chamber 208 is filledwith fluid, drain apparatus inlet valve 242 is closed to preventadditional disinfectant fluid from entering the chamber 208 via theinlet line 210. Once the chamber 208 is filled with disinfectant fluid,the disinfectant fluid is allowed to dwell in the chamber 208 for apredetermined amount of time. In some implementations, once the pressuresensor 240 detects that the pressure in the chamber 208 has reached athreshold pressure indicating that the chamber 208 is filled with fluid,a signal is sent to close the water inlet valve 510 in order to preventadditional water from being added to the dialysis circuit 500 via thewater inlet port 502 and stop the production of disinfectant fluid.After the disinfectant fluid has dwelled in the chamber 208 for thepredetermined amount of time, the drain apparatus outlet valve 216 isopened and the drain apparatus pump 214 draws the disinfectant fluid outof the chamber 208 through outlet port 206 and the open drain apparatusoutlet valve 216 to the drain line 112 via the outlet line 212.

As depicted in FIG. 10, in some implementations, the lid 922 of thedrain apparatus 920 is not liquid-tight when in a closed position andthe chamber 208 of the drain apparatus 920 is filled with disinfectantfluid during disinfection by metering the flow of disinfectant fluidinto inlet line 210 of the drain apparatus 920 using the balancingdevices 554, 556 of the dialysate circuit 500. For example, once thedrain apparatus inlet valve 242 is opened during disinfection, theamount of disinfectant fluid exiting the balancing devices 554, 556towards the drain apparatus 920 can be controlled to provide the exactamount of disinfectant fluid required to fill the fluid line between thebalancing devices 554, 556 and the inlet line 210, the inlet line 210,and the chamber 208 of the drain apparatus 920. In this arrangement, asdisinfectant fluid enters the chamber 208, an equal amount of aircontained in the chamber 208 exits the chamber 208 around thenon-liquid-tight lid 922. In some implementation, the lid 922 of thedrain apparatus 920 includes vents or holes (such as holes 924 of FIG.9). In some examples, each stroke of the balancing devices 554, 556provides 30 ccs of disinfectant fluid to the drain apparatus 920 via theinlet line 210, and a calculated number of strokes of the balancingdevices 554, 556 are performed in order to provide the amount ofdisinfectant fluid necessary to fill the chamber 208 of the drainapparatus 920. Once the chamber 208 is filled with disinfectant fluid,drain apparatus outlet valve 216 remains closed to allow thedisinfectant fluid to dwell in the chamber 208 for a predeterminedamount of time. After the disinfectant fluid has dwelled in the chamber208 for the predetermined amount of time, the drain apparatus outletvalve 216 is opened and the drain apparatus pump 214 draws thedisinfectant fluid out of the chamber 208 through outlet port 206 andthe open drain apparatus outlet valve 216 to the drain line 112 via theoutlet line 212.

Referring to FIG. 11, in some implementations, the lid 932 of the drainapparatus 930 is not liquid-tight when in a closed position and thedrain apparatus 932 includes an ultrasound sensor 904 coupled to theouter funnel 220 is configured to detect the liquid level 906 inside thechamber 208 of the drain apparatus 930. For example, duringdisinfection, the level of disinfectant fluid in the chamber 208 of thedrain apparatus 930 is monitored by the ultrasound sensor 904. Duringdisinfection, drain apparatus outlet valve 216 is closed anddisinfectant fluid is provided to the chamber 208 of the drain apparatus930 via the inlet line 210. In this arrangement, as disinfectant fluidenters the chamber 208, an equal amount of air contained in the chamber208 exits the chamber 208 around the non-liquid-tight lid 932. In someimplementation, the lid 932 of the drain apparatus 930 includes vents orholes (such as holes 924 of FIG. 9). Once the ultrasound sensor 904detects that level 906 of disinfectant fluid is at or near the top ofthe chamber 208, the drain apparatus valve 242 is closed to prevent anyadditional disinfectant fluid from entering the chamber 208 of the drainapparatus 930 and the disinfectant fluid is allowed to dwell in thechamber 208 for a predetermined amount of time. In some implementations,once the ultrasound sensor 904 detects that the liquid level 906 is ator near the top of the chamber 208 such that the chamber 208 is filledwith fluid, a signal is sent to close the water inlet valve 510 in orderto prevent additional water from being added to the dialysis circuit 500via the water inlet port 502 and stop the production of disinfectantfluid. After the disinfectant fluid has dwelled in the chamber 208 forthe predetermined amount of time, the drain apparatus outlet valve 216is opened and the drain apparatus pump 214 draws the disinfectant fluidout of the chamber 208 through outlet port 206 and the open drainapparatus outlet valve 216 to the drain line 112 via the outlet line212.

Referring to FIG. 12, in some implementations, the lid 942 of the drainapparatus 940 is not liquid-tight when in a closed position and one ormore electrodes 908 are positioned within the chamber 208 of the drainapparatus and configured to detect the level of chemical disinfectantfluid 906 inside the chamber 208 of the drain apparatus 940. Forexample, the one or more electrodes 908 may be attached to the top ofthe inner funnel 218 of the drain apparatus and configured to interactwith disinfectant fluid. During disinfection, drain apparatus outletvalve 216 is closed and disinfectant fluid is provided to the chamber208 of the drain apparatus 940 via the inlet line 210. In thisarrangement, as disinfectant fluid enters the chamber 208, an equalamount of air contained in the chamber 208 exits the chamber 208 aroundthe non-liquid-tight lid 942. In some implementation, the lid 942 of thedrain apparatus 940 includes vents or holes (such as holes 924 of FIG.9). Once the chemical disinfectant fluid is at or near the top of thechamber 208, the chemicals in the disinfectant fluid will interact withthe one or more electrodes 908 located near the top of the chamber 208,indicating that the chamber 208 is full of disinfectant fluid. In someimplementations, once the one or more electrodes 908 detect that thelevel 906 of disinfectant fluid is at or near the top of the chamber208, the drain apparatus valve 242 is closed to prevent any additionaldisinfectant fluid from entering the chamber 208 of the drain apparatusand the disinfectant fluid is allowed to dwell in the chamber 208 for apredetermined amount of time. In some implementations, once the one ormore electrodes 908 detect that the level 906 of disinfectant fluid isat or near the top of the chamber 208, a signal is sent to close thewater inlet valve 510 in order to prevent additional water from beingadded to the dialysis circuit 500 via the water inlet port 502 and stopthe production of disinfectant fluid. After the disinfectant fluid hasdwelled in the chamber 208 for the predetermined amount of time, thedrain apparatus outlet valve 216 is opened and the drain apparatus pump214 draws the disinfectant fluid out of the chamber 208 through outletport 206 and the open drain apparatus outlet valve 216 to the drain line112 via the outlet line 212. Any of various suitable electrodes can beused to detect fluid levels, such as an in-line tube electrode with anoptical slot, a conductive rod probe, etc.

As depicted in FIG. 13, in some implementations, the lid 952 of thedrain apparatus 950 is not liquid-tight when in a closed position andthe drain apparatus 950 includes an ultrasonic transmitter 910 andultrasonic receiver 912 configured to detect the liquid level 906 insidethe chamber 208 of the drain apparatus 950. In this arrangement, asdisinfectant fluid enters the chamber 208, an equal amount of aircontained in the chamber 208 exits around the non-liquid-tight lid 958.In some implementation, the lid 952 of the drain apparatus 950 includesvents or holes (such as holes 924 of FIG. 9). As shown in FIG. 13, theultrasonic transmitter 910 and ultrasonic receiver 912 can be coupled tothe inside surface 914 of lid 952 of the drain apparatus 950 facingtowards the chamber 208 of the drain apparatus 950 when the lid 952 isin a closed position. During disinfection, drain apparatus outlet valve216 is closed, lid 950 is closed over the chamber 208, disinfectantfluid is provided to the chamber 208 of the drain apparatus 950 via theinlet line 210, and the ultrasonic transmitter 910 transmits soundwavesthrough the lid 952 to the chamber 208. The soundwaves transmitted byultrasonic transmitter 910 bounce off the surface of liquid in thechamber 208 and are received by the ultrasonic receiver 912. Based onthe intensity of the soundwaves received by the ultrasonic receiver 912,the level 906 of disinfectant fluid in the chamber 208 of the drainapparatus 950 can be determined. Once the sound waves received by theultrasonic receiver 912 indicate that level 906 of disinfectant fluid isat or near the top of the chamber 208, the drain apparatus valve 242 isclosed to prevent any additional disinfectant fluid from entering thechamber 208 of the drain apparatus. In some implementations, once thesound waves received by the ultrasonic receiver 912 indicate that theliquid level 906 is at or near the top of the chamber 208, a signal issent to close the water inlet valve 510 in order to prevent additionalwater from being added to the dialysis circuit 500 via the water inletport 502 and stop the production of disinfectant fluid. After thedisinfectant fluid has dwelled in the chamber 208 for the predeterminedamount of time, the drain apparatus outlet valve 216 is opened and thedrain apparatus pump 214 draws the disinfectant fluid out of the chamber208 through outlet port 206 and the open drain apparatus outlet valve216 to the drain line 112 via the outlet line 212. Any of varioussuitable ultrasonic transmitters and receivers can be used to detectfluid levels, such as an ultrasonic gap sensor.

Referring to FIG. 14, in some implementations, the lid 962 of the drainapparatus 960 is not liquid-tight when in a closed position and thedrain apparatus 962 includes a light transmitter 916 and light receiver918 configured to detect the liquid level 906 inside the chamber 208 ofthe drain apparatus 960. In this arrangement, as disinfectant fluidenters the chamber 208, an equal amount of air contained in the chamber208 exits around the non-liquid-tight lid 962. In some implementation,the lid 962 of the drain apparatus 960 includes vents or holes (such asholes 924 of FIG. 9). As shown in FIG. 14, the light transmitter 916 andlight receiver 918 can be coupled to the inside surface 964 of lid 962of the drain apparatus 960 facing towards the chamber 208 of the drainapparatus 960 when the lid 962 is in a closed position. Duringdisinfection, drain apparatus outlet valve 216 is closed, lid 962 isclosed over the chamber 208, disinfectant fluid is provided to thechamber 208 of the drain apparatus 960 via the inlet line 210, and thelight transmitter 916 transmits light waves into the chamber 208. Thelight waves transmitted by light transmitter 916 bounce off the surfaceof liquid in the chamber 208 and are received by the light receiver 918.Based on the intensity of the light waves received by the light receiver918, the level 906 of disinfectant fluid in the chamber 208 of the drainapparatus 960 can be determined. Once the light waves received by thelight receiver 918 indicate that level 906 of disinfectant fluid is ator near the top of the chamber 208, the drain apparatus valve 242 isclosed to prevent any additional disinfectant fluid from entering thechamber 208 of the drain apparatus. In some implementations, once thelight waves received by the light receiver 918 indicate that the liquidlevel 906 is at or near the top of the chamber 208, a signal is sent toclose the water inlet valve 510 in order to prevent additional waterfrom being added to the dialysis circuit 500 via the water inlet port502 and stop the production of disinfectant fluid. After thedisinfectant fluid has dwelled in the chamber 208 for the predeterminedamount of time, the drain apparatus outlet valve 216 is opened and thedrain apparatus pump 214 draws the disinfectant fluid out of the chamber208 through outlet port 206 and the open drain apparatus outlet valve216 to the drain line 112 via the outlet line 212. Any of varioussuitable light transmitters and receivers can be used to detect fluidlevels, such as an optical switch sensor.

Referring to FIG. 15, in some implementations, the lid 972 of the drainapparatus 970 is not liquid-tight when in a closed position and thedrain apparatus 970 includes a level sensor 974 coupled to the drainapparatus 970. Level sensor 974 is configured to detect the liquid level906 inside the chamber 208 of the drain apparatus 970. For example,during disinfection, the level of disinfectant fluid in the chamber 208of the drain apparatus 970 is monitored by the level sensor 974. Duringdisinfection, drain apparatus outlet valve 216 is closed anddisinfectant fluid is provided to the chamber 208 of the drain apparatus970 via the inlet line 210. In this arrangement, as disinfectant fluidenters the chamber 208, an equal amount of air contained in the chamber208 exits the chamber 208 around the non-liquid-tight lid 972. In someimplementations, the lid 972 of the drain apparatus 970 includes ventsor holes (such as holes 924 of FIG. 9). Once the level sensor 974detects that level 906 of disinfectant fluid is at or near the top ofthe chamber 208, the drain apparatus valve 242 is closed to prevent anyadditional disinfectant fluid from entering the chamber 208 of the drainapparatus 970 and the disinfectant fluid is allowed to dwell in thechamber 208 for a predetermined amount of time. In some implementations,once the level sensor 974 detects that the liquid level 906 is at ornear the top of the chamber 208 such that the chamber 208 is filled withfluid, a signal is sent to close the water inlet valve 510 in order toprevent additional water from being added to the dialysis circuit 500via the water inlet port 502 and stop the production of disinfectantfluid. After the disinfectant fluid has dwelled in the chamber 208 forthe predetermined amount of time, the drain apparatus outlet valve 216is opened and the drain apparatus pump 214 draws the disinfectant fluidout of the chamber 208 through outlet port 206 and the open drainapparatus outlet valve 216 to the drain line 112 via the outlet line212. Any of various suitable level sensors can be used, such as a levelswitch, a magnetic level switch, a magnetic float sensor, a pneumaticlevel sensor, an electrode level sensor, a conductivity level sensor,etc.

While the methods described above for disinfecting the drain apparatus200 involve allowing the disinfectant fluid to dwell in the chamber 208of the drain apparatus 200 for a predetermined amount of time, othertechniques can alternatively or additionally be used. In someimplementations, for example, once the chamber 208 of drain apparatus200 is filled with disinfectant fluid (as determined using the methodsabove), the drain apparatus outlet valve 216 is opened to allowdisinfectant fluid to flow through the outlet line 212 to the drain line112, and additional disinfectant fluid is simultaneously provided to thechamber 208 via the inlet line 210. In some implementations, once thechamber 208 is filled with disinfectant fluid and the outlet valve 216has been opened, the dialysate circuit 500 pumps disinfectant fluid tothe chamber 208 via the inlet line 210 at a rate sufficient to maintainthe disinfectant fluid level 906 in chamber 208 (i.e., keep the chamberfilled with disinfectant fluid). This “continuous flow” method ofdraining and simultaneously filling of the chamber 208 of the drainapparatus 200 can be performed for a predetermined amount of time toensure that the chamber 208 is properly disinfected. In someimplementations, the disinfectant fluid continuously flows through andfills the chamber 208 for at least 10 minutes (e.g., at least 30minutes, 10 to 60 minutes). In some examples, after the disinfectantfluid has been flowing and filling the chamber 208 for the predeterminedamount of time, the drain apparatus inlet valve 242 is closed and thesolution contained in the chamber 208 of the drain apparatus 200 exitsthe chamber 208 through drain apparatus outlet valve 216 via the outletline 212 to the drain line 112.

Further, while the disinfectant fluid used to disinfect the dialysatecircuit 500 and the drain apparatus 200 has been described as includinga chemical disinfectant concentrate, the disinfectant fluid canalternatively be composed of hot water alone (i.e., without the additionof chemical disinfectant concentrate). In some examples, thedisinfectant fluid is heated to a temperature of at least 80° C.

While the hydrophobic filter 232 of the drain apparatus 200 has beendescribed as being arranged within the vent 230 of the drain apparatus,the hydrophobic filter 232 can alternatively be incorporated into thelid 952 of the drain apparatus 200. For example, the lid 952 can includean opening therethrough and the hydrophobic filter 232 can be arrangedwithin the opening in the lid 202.

While the lid 202 has been described as being attached to the drainapparatus 200 using a hinge 238, the lid 202 can be attached to thedrain apparatus 200 using alternative attachment mechanisms, such asclips, threads, an injection molded attachment, magnets, etc. In someexamples, the lid 202 is attached to the drain apparatus 200 along apivoting axis such that that lid 202 can be pivoted along to the axis tocover the drain apparatus 200. In some implementations, the lid 202 ispivoted about an axis by a stepper motor attached to the lid 202. Insome embodiments, the lid 202 may be unattached from the drain apparatus200 and can be placed on top of the apparatus 200 to seal the chamber208, such as during disinfection of the chamber.

While the methods above involve attaching only the venous patient line108 to the drain apparatus 200 during priming and following treatment,the arterial patient line 106 may additionally or alternatively beattached to the drain apparatus 200 to prime and flush the arterialpatient line 106. For example, referring to FIG. 18, before priming thehemodialysis system 100, both the patient end 628 of the arterialpatient line 106 and the patient end 630 of the venous patient line 108can be attached to the drain apparatus 200 using the clip(s) 226 of thedrain apparatus. A first end of the saline delivery line 126 can beattached to the saline bag 138 and a second end of the saline deliveryline 126 can be attached to a port 702 on the arterial patient line 106.To begin priming the system 100, saline is introduced from the salinebag 138 through the saline delivery line 126 and through the port 702 onthe arterial line 106. Saline is first provided to the portion of thearterial patient line 106 between the patient end 126 of the arterialpatient line 106 and the port 702 on the arterial patient line 106.

Once the portion of the arterial patient line 106 between the patientend 126 of the arterial patient line 106 and the port 702 on thearterial patient line 106 is filled with saline, a clamp proximate thepatient end 126 of the arterial patient line 106 is clamped. The bloodpump 132 is then turned on to draw saline from the saline bag 138,through saline delivery line 126 and the port 702 on the arterialpatient line 106, through a portion of the arterial patient line 106between the port 702 on the arterial patient line 106 and the dialyzer110. The saline flows into the dialyzer 110 via the dialyzer inlet line134 and exits the dialyzer 110 via the dialyzer outlet line 136.

As the saline flows through the dialyzer outlet line 136 towards the airrelease device 608, the saline passes through the venous pressure sensor606. Next, the saline flows through an entry port of the air releasedevice 608 and fills the air release device 608. Once the air releasedevice 608 is filled with saline, a clamp on the venous patient line 108is removed and saline flows through the venous patient line 108 towardsthe patient end 630 of the venous patient line 108. Once the entireblood circuit 700 is filled with saline, any additional (e.g., excess)saline pumped through the blood component set 104 exits the patient end630 of the venous patient line 108 and is captured by the chamber 208 ofthe drain apparatus 200. Once all air is out of the patient lines 106,108 and the blood circuit 700 is filled with saline, a clamp is closedon the patient end 630 of the venous patient line 108. Once clamped, thepatient ends 628, 630 of the patient lines 106, 108 are removed from thedrain apparatus 200.

Similarly, in some implementations, both the arterial patient line 106and the venous patient line 106 can be attached to the drain apparatus200 to flush the patient lines 106, 108 following dialysis. For example,referring to FIG. 18, once a desired amount of the blood containedwithin the blood circuit 700 has been reinfused back to the patient 602,the patient lines 106, 108 are clamped, removed from the patient 602,and both the patient end 628 of the arterial patient line 106 and thepatient end 630 of the venous patient line 108 are attached to the drainapparatus 200 using the clip(s) 226. A first end of the saline deliveryline 126 can be attached to a saline bag 138 and a second end of thesaline delivery line 126 can be attached to a port 702 on the arterialpatient line 106. Saline is introduced from the saline bag 138 throughthe port 702 on the arterial line 106 via the saline delivery line 126.

Saline is first provided to the portion of the arterial patient line 106between the patient end 126 of the arterial patient line 106 and theport 702 on the arterial patient line 106. The saline exits the patientend 628 of the arterial patient line 106 into the chamber 208 of thedrain apparatus. Saline is continuously provided until all remainingpatient fluids in the portion of the arterial patient line 106 betweenthe patient end 126 of the arterial patient line 106 and the port 702 onthe arterial patient line 106 have been flushed into the drain apparatus200.

Once the portion of the arterial patient line 106 between the patientend 126 of the arterial patient line 106 and the port 702 on thearterial patient line 106 is flushed of patient fluids, a clampproximate the patient end 126 of the arterial patient line 106 isclamped. The blood pump 132 is then turned on to draw saline from thesaline bag 138 through the saline delivery line 126 and the port 702 onthe arterial patient line 106 and circulate saline throughout allcomponents of the blood circuit 700. After circulating through the bloodcircuit 700, the saline exits the patient end 630 of the venous patientline 108 and collects in the chamber 208 of the drain apparatus 200. Thedrain apparatus outlet valve 216 is open and the drain apparatus pump214 is turned on to draw the saline collected from the venous patientline 108 by the drain apparatus 200 to the drain line 112 via the outletline 212. Saline is continuously pumped through the blood circuit 700until all remaining patient fluids have been flushed from the bloodcircuit 700 into the drain apparatus 200. In some cases, for example,saline is pumped through the blood circuit 700 until the saline bag 138is empty.

While the drain apparatus 200 has been described as including a clip 226to attach the venous patient line 108 to the drain apparatus 200, othermechanical attachment devices, such as clamps, ties, straps, hooks,latches, etc., can alternatively or additionally be used to attach thepatient line(s) 106, 108 to the drain apparatus. In someimplementations, the drain apparatus 200 includes two or more mechanicalattachment devices.

While the drain apparatus 200 has been described as including a coupler234 to attach the vent 230 to the lid 202 of the drain apparatus 200, insome examples the vent is coupled to the lid without a separate coupler.For example, as depicted in FIG. 17, drain apparatus 800 includes a vent830 with a clip portion 832 that is configured to flex and fill anopening 834 in the lid 802 and couple the vent 830 to the lid 802. Theclip portion 832 of the vent 830 is semi-rigid and compresses to fitinto the opening 834 of the lid 802. In addition, once positioned withinthe opening 834, the clip portion 832 of the vent 830 expands to securethe vent 830 in place within the opening 834. In order to remove thevent 830 from the lid 802, a force is applied to the vent 830 and thediameter of the clip portion 832 of the vent 830 is compressed so thatthe clip portion 832 can slide out of the opening 834 of the lid 802.Once removed from the lid 802, the clip portion 832 of the vent 830expands to its original, uncompressed diameter. In some examples, thevent 830 is replaced as part of periodic maintenance. In someimplementations, a plurality of pores in hydrophobic filter 232 close inresponse to contact with water, and vent 830 is replaced followingclosure of the pores in the hydrophobic filter 232.

In some examples, a leak detection sensor is positioned below the drainapparatus 200 (e.g., proximate the outlet port 206 of the drainapparatus) to detect malfunctions in the drain apparatus 200 resultingin fluid leaks from the drain apparatus 200. The leak detection sensorcan be communicably coupled to the drain apparatus inlet valve 242 andthe drain apparatus inlet valve 242 can be automatically closed inresponse to the leak detection sensor detecting fluid leaking from thedrain apparatus 200.

While the arterial pressure sensor 604 has been described as beingarranged upstream of the blood pump 116 to measure a pre-pump arterialpressure, it can alternatively be positioned downstream of the bloodpump 116 to measure a post-pump arterial pressure, or an additionalarterial pressure sensor can be positioned downstream of the blood pump116 to measure a post-pump arterial pressure.

While the methods above involve circulating saline through the patientlines 106, 108 and the blood circuit 600 to flush the patient lines 106,108 and blood circuit of any remaining patient fluids, alternatively airmay be pumped through the blood circuit 600 and patient lines 106, 108to flush the patient lines 106, 108 and blood circuit 600 of anyremaining patient fluids. For example, the arterial patient line 106 canbe disconnected from the saline delivery line 126, and blood pump 116can be used to draw air through the blood circuit 600 via the arterialpatient line 106.

While the methods above involve using valves 538 through 552 to controlflow of disinfectant fluid to alternate the flow of disinfectant fluidbetween the first chamber halves 558, 560 and second chamber halves 562,564, alternatively all of the balancing device valves 538 through 552can be opened during disinfection of the dialysate circuit 500. Forexample, during disinfection, all of valve 538 through 552 can be opensuch that disinfectant fluid flowing out of mixing chambers 534, 536flows into all four chamber halves 558, 560, 562, 564 simultaneously.

While the methods above involve disinfectant fluid flowing into thesecond chamber halves 562, 564 of the balancing devices 554, 556 fromthe air separation chamber 593 and disinfectant fluid flowing out of thesecond chamber halves 562, 564 through valves 548, 552, alternativelyvalves 548 and 552 can remain closed during disinfection, such that asdisinfectant fluid flows into first chamber half 558 of balancingdevices 554, disinfectant fluid is simultaneously forced out of thesecond chamber half 562 of balancing device 554 and into the secondchamber half 564 of balancing device 556. Similarly, in someimplementations, as disinfectant fluid flows into first chamber half 560of balancing devices 556, disinfectant fluid is simultaneously forcedout of the second chamber half 564 of balancing device 556 and into thesecond chamber half 562 of balancing device 554.

A number of embodiments have been described. Nevertheless, it will beunderstood that various modifications may be made without departing fromthe spirit and scope of the disclosure. Accordingly, other embodimentsare within the scope of the following claims.

What is claimed is:
 1. A dialysis system, comprising: a dialysis machinecomprising a fluid line and a drain line; a blood line set configured tobe connected to the dialysis machine; a drain apparatus coupled to thedialysis machine, the drain apparatus comprising a chamber configured toreceive an end of a patient line of the blood line set; an inlet linehaving a first end configured to be coupled to the chamber and a secondend configured to be coupled to the fluid line of the dialysis machine;an outlet line having a first end configured to be coupled to thechamber and a second end configured to be coupled to the drain line ofthe dialysis machine; and a valve coupled to the outlet line andconfigured to control flow of fluid through the outlet line.
 2. Thedialysis system of claim 1, wherein the fluid line and the drain lineare parts of a hydraulic circuit of the dialysis machine, the dialysissystem further comprising a dialyzer connected to the hydraulic circuitof the dialysis machine.
 3. The dialysis system of claim 2, wherein thedrain line is downstream of the dialyzer.
 4. The dialysis system ofclaim 3, wherein the fluid line is upstream of the dialyzer.
 5. Thedialysis system of claim 1, wherein the second end of the outlet line isconfigured to be coupled to the drain line at a location upstream of apost-dialyzer flow pump of the dialysis machine.
 6. The dialysis systemof claim 1, wherein the second end of the outlet line is configured tobe coupled to the drain line at a location of the dialysis machinedownstream of a drain valve of the dialysis machine.
 7. The dialysissystem of claim 1, wherein the drain apparatus further comprises a pumpcoupled to outlet line and configured to pump fluid from the chamber ofthe drain apparatus to the drain line of the dialysis machine.
 8. Thedialysis system of claim 1, wherein the drain apparatus is configured todrain fluid contained in the chamber of the drain apparatus through theoutlet line of the drain apparatus to the drain line of the dialysismachine by gravity when the valve of the drain apparatus is in an openposition.
 9. The dialysis system of claim 1, wherein the second end ofthe inlet line is configured to be coupled to a portion of the fluidline downstream of a fluid filter of the dialysis machine.
 10. Thedialysis system of claim 1, wherein the drain apparatus furthercomprises a lid coupled to the chamber and configured to form a sealwith the chamber.
 11. The dialysis system of claim 10, wherein the lidincludes a vent and a hydrophobic filter disposed within the vent.
 12. Adrain apparatus for a dialysis machine, the drain apparatus comprising:a chamber configured to receive an end of a fluid line extending fromthe dialysis machine; a lid configured to be coupled to the chamber toform a seal with the chamber; an inlet line having first end configuredto be coupled to the chamber and a second end configured to be coupledto a fluid line of the dialysis machine; an outlet line having a firstend configured to be coupled to the chamber and a second end configuredto be coupled to a drain line of the dialysis machine; and a valvecoupled to the outlet line and configured to control flow of fluidthrough the outlet line.
 13. The drain apparatus of claim 12, whereinthe chamber comprises an inner funnel coupled to and nested within anouter funnel.
 14. The drain apparatus of claim 13, wherein the innerfunnel and outer funnel form an annular channel and the first end of theinlet line is fluidly connected to the annular channel.
 15. The drainapparatus of claim 14, wherein the annular channel is formed between anouter surface of the inner funnel and an inner surface of the outerfunnel.
 16. The drain apparatus of claim 12, further comprising a pumpcoupled to the outlet line.
 17. The drain apparatus of claim 12, furthercomprising one or more mechanical attachment devices coupled to thechamber and configured to position the end of a patient line extendingfrom the dialysis machine inside the chamber.
 18. The drain apparatus ofclaim 12, further comprising: a vent extending through the lid; and ahydrophobic membrane coupled to the vent.
 19. The drain apparatus ofclaim 12, further comprising a sensor configured to detect a fluid levelin the chamber.
 20. The drain apparatus of claim 19, wherein the sensorcomprises a pressure sensor coupled to the outlet line.
 21. The drainapparatus of claim 19, wherein the sensor comprises an ultrasound sensorcoupled to the chamber.
 22. The drain apparatus of claim 19, wherein thesensor comprises an ultrasonic sensor and an ultrasonic receiver coupledto the lid.
 23. The drain apparatus of claim 19, wherein the sensorcomprises a light transmitter and a light receiver coupled to the lid.24. The drain apparatus of claim 19, wherein the sensor comprises one ormore electrodes coupled to the chamber.
 25. The drain apparatus of claim12, wherein the lid comprises one or more vent holes.
 26. A methodcomprising: emptying contents of a blood line set of a dialysis systeminto a chamber of a drain apparatus of the dialysis system; closing alid of the drain apparatus to seal the chamber of the drain apparatus;flowing a disinfectant fluid through an inlet line of the drainapparatus from a dialysis machine of the dialysis system to the drainapparatus to at least partially fill the chamber of the drain apparatuswith the disinfectant fluid; and flowing the disinfectant fluid throughan outlet line of the drain apparatus from the drain apparatus to adrain line of the dialysis machine.
 27. The method of claim 26, whereinemptying contents of a blood line set of a dialysis system into achamber of a drain apparatus of the dialysis system comprises:connecting a patient line of the blood line set to the drain apparatusof the dialysis machine following performance of dialysis on a patient;flowing a saline solution through the patient line of the blood line setinto the drain apparatus to flush remaining fluid in the blood line setinto the drain apparatus; and disconnecting the patient line of theblood line set from the drain apparatus.
 28. The method of claim 26,further comprising stopping flow of the disinfectant fluid uponreceiving a signal from a sensor coupled to the drain apparatusindicating that the chamber of the drain apparatus is filled withdisinfectant solution.
 29. The method of claim 26, wherein thedisinfectant fluid dwells in the chamber of the drain apparatus for apredetermined amount of time.
 30. The method of claim 26, whereinflowing the disinfectant fluid through the outlet line of the drainapparatus from the drain apparatus to the drain line of the dialysismachine comprises opening a valve coupled to the outlet line of thedrain apparatus.
 31. The method of claim 26, wherein flowing thedisinfectant fluid through the outlet line of the drain apparatus fromthe drain apparatus to the drain line of the dialysis machine comprisespumping the disinfectant fluid in the chamber of the drain apparatus tothe drain line using a pump coupled to the outlet line of the drainapparatus.
 32. The method of claim 26, wherein flowing the disinfectantfluid through the outlet line of the drain apparatus from the drainapparatus to the drain line of the dialysis machine comprises usingnegative pressure generated by a flow pump of the dialysis machine topump the disinfectant fluid in the chamber of the drain apparatus to thedrain line.
 33. The method of claim 26, wherein the disinfectant fluidcomprises a chemical disinfectant.
 34. The method of claim 26, whereinthe disinfectant fluid is hot water.
 35. The method of claim 26, whereinflowing the disinfectant fluid through the inlet line of the drainapparatus from the dialysis machine to the drain apparatus to at leastpartially fill the chamber of the drain apparatus comprises flowing thedisinfectant fluid into the chamber at a rate sufficient to maintain apredetermined level of fluid in the chamber for a predetermined amountof time.